JPS63289256A - Fuel injection device - Google Patents

Abstract

PURPOSE:To enhance the open/close responsiveness of injection hole by constituting so that a valve body which opens or closes an injection hole by the excitation of an exciting coil is energized in the open direction, and further that this valve body can be energized in the close direction by magnetic repulsive forces. CONSTITUTION:When an exciting current is applied to an exciting coil 15 on the basis of an injection command signal, a magnetic circuit is formed among a core 7, an armature 23, and a yoke 9, and the armature 23 is magnetically attracted to the upper surface side of the core 7 against the magnetic repulsive forces of a first and a second permanent magnets 27, 29 to open a valve body 25. Then, the pressurized fuel supplied into a housing 3 via fuel supply holes 3c, 9a, and 3d is injected through an injection hole 5a. Thereafter, if the application of exciting current to the exciting coil 15 is interrupted, the valve body 25 is moved upward by the magnetic repulsive forces of respective permanent magnets 27, 29, and the injection hole 5a is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device for supplying fuel to an internal combustion engine.

[Prior Art] For example, in a solenoid valve of a fuel injection device disclosed in Japanese Patent Application Laid-Open No. 60-60383, a valve body such as a needle valve or a ball valve opens and closes an injection hole formed in a valve seat at one end of a housing. an elastic member such as a coil spring that always urges the mover so that the injection hole is closed by the valve body, and a mover that resists the elastic force of the elastic member. It consists of an electromagnetic solenoid that is moved to open the injection hole. Then, the movable element is moved against the elastic force of the elastic member by an electromagnetic solenoid driven based on an injection command signal output from the fuel injection control device to release the closure of the injection hole by the valve body, and the inside of the housing is The pressurized fuel is supplied to the internal combustion engine through the open injection holes.

[Problem to be Solved by the Invention 1] However, in the fuel injection device having the structure described above, when the electromagnetic solenoid is energized, the injection hole is opened by the movable member that moves against the elastic force of the elastic member. Since the injection hole was opened, the opening/closing response of the injection hole was poor.

For this reason, it has been difficult to efficiently supply an optimal amount of fuel according to the required air-fuel ratio of the internal combustion engine.

Furthermore, since the elastic force of the elastic member changes with use over time, it has been difficult to stably supply fuel over a long period of time.

[Object of the Invention] In view of the above-mentioned conventional drawbacks, an object of the present invention is to improve the opening/closing response of the injection hole to stably supply an optimal amount of fuel over a long period of time according to the required air-fuel ratio of the internal combustion engine. The object of the present invention is to provide a fuel injection device that can perform the following steps.

Means for Solving Problem L] For this reason, the present invention provides a housing that is provided at one end of a hollow housing. a valve seat with an injection hole formed in its center, a valve body that opens and closes the injection hole, and first and second permanent magnets that bias the valve body with magnetic repulsion to close the injection hole; A fuel injection device is constituted by an excitation coil that magnetically attracts the valve body against magnetic repulsion by the first and second permanent magnets and opens the injection hole.

[Operation of the Invention] Since the present invention is configured as described above, when the excitation coil is not energized, the injection hole of the valve seat is energized by the valve body which is biased by the magnetic repulsion of the first and second permanent magnets. Closed. This restricts fuel injection to the internal combustion engine. Also,
When the excitation coil is excited, the injection hole is opened by a valve body that is magnetically attracted by lines of magnetic force generated from the excitation coil against the magnetic repulsion of the first and second permanent magnets;
Fuel supplied into the housing through the injection hole is injected into the internal combustion engine. As a result, it is possible to improve the opening/closing response of the injection hole by the valve body, and to inject an optimal amount of fuel into the internal combustion engine according to its required air-fuel ratio.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a fuel injection device according to the present invention, and FIG.
The figure is a central vertical cross-sectional view of the assembled fuel injection device.
The housing 3 of the fuel injection device 1 is made of a metal material and is formed into a substantially hollow cylindrical shape having a small diameter portion 3a at the top and a large diameter portion 3b at the bottom. A valve seat 5 having an injection hole 5a in the center is attached to the small diameter portion 3a of the housing 3. Further, inside the large diameter portion 3b of the housing 3, there is a magnetic member 11 made of a magnetic material having high saturation magnetic flux density characteristics, and having a core 7 in the center and a cylindrical yoke 9 on the outer circumferential side integrally formed with the magnetic member 11. It is provided so as to form a required upper space 13 between the valve seat 5 and the valve seat 5 . An excitation coil 15 in which a large number of electric wires are wound is attached to the core 7, and each lead end of the excitation coil 15 is made of synthetic resin and inserted into a through hole 17 formed around the lower end of the core 7. Each terminal 2 protrudes outside the housing 3 via the insulating member 19
1, respectively. Fuel supply holes 3C and 9a are formed in the housing 3 and the yoke 9 so as to pass through each other and communicate with the lower space 16 between the core 7 and the yoke 9. Furthermore, a fuel supply hole 3d is formed in the case 3 corresponding to the upper space 13. Then, fuel pressurized to a required pressure by a fuel pump (not shown) flows into the lower space 16 through the fuel supply holes 3C and 9a, and into the upper space 13 through the fuel supply hole 3d. The fuel supplied into the upper space 13 and the lower space 16 is supplied to the arm portion 2 of the armature 23, which will be described later.
3b. As a result, the valve body 2 described later
Fuel is applied to the outer and inner surfaces of 5 at approximately equal pressure.

A plurality of support shafts 9b are integrally formed on the upper end surface of the yoke 9, and the support shafts 9b are made of a magnetic material having a high saturation magnetic flux density characteristic similar to that of the magnetic member 11. An armature 23 integrally formed with a number of arm portions 23b extending in a centripetal direction corresponding to the outer peripheral edge of the upper end is supported so as to be movable in the axial direction. A dome-shaped valve body 25 made of a titanium alloy or the like having high hardness is attached to the tip of each arm 23b. Further, a first permanent magnet 27 is provided on the upper end surface of the core 7, and a valve body 2
A second permanent magnet 29 is attached to the inner surface of the top of each of the magnets 5,
These first and second permanent magnets 27 and 29 are arranged so that the same magnetic poles face each other. The armature 23 is moved upward by the magnetic repulsion of the first and second permanent magnets 27 and 29 so that the outer peripheral surface of the top of the valve body 25 comes into contact with the lower surface of the valve seat 5 corresponding to the lower end opening of the injection hole 5a. be done.

A guide bottle 31 is attached to the upper surface of the top of the valve body 25 so as to be located within the injection hole 5a, and the guide bottle 31 forms atomized fuel to be injected from the injection hole 5a into the internal combustion engine. Ru.

Next, the operation of the fuel injection device 1 configured as described above will be explained with reference to FIGS. 2 and 3.

First, the non-injection state of fuel will be explained according to Fig. 2.
When the excitation current a is not applied to the excitation coil 15, the valve body 25 is moved upward by the magnetic repulsion force generated by the first permanent magnet 27 and the second permanent magnet 29, and the top surface of the valve body 25 is brought into contact with the lower end opening of the injection hole 5a. The valve seat 5 is brought into contact with the corresponding lower surface of the valve seat 5. As a result, the injection hole 5a is closed by the valve body 25, and the fuel pressurized and supplied into the housing 3 through the fuel supply holes 3C, 9a and 3d is restricted from being injected into the internal combustion irgJ.

8f indicates the fuel injection status! In FIG. 3, when an excitation current is applied to the excitation coil 15 based on an injection command signal from a fuel injection control device (not shown) in the above state, a voltage is generated between the core 7, the armature 23, and the yoke 9. A magnetic circuit is formed by lines of magnetic force generated as the coil 15 is excited. As a result, the armature 23 is connected to the first and second armatures.
It is magnetically attracted to the upper surface side of the core 7 against the magnetic repulsion of the permanent magnets 27 and 29, and the injection hole 5a is released from being closed by the valve body 25. The fuel pressurized and supplied into the housing 3 through the fuel supply holes 3c, 9a, and 3d by the above operation is injected into the internal combustion engine through the opened injection hole 5a. At this time, the fuel injected into the internal combustion engine is
1, it is formed into a spray form and its mixing ratio with air is increased.

When the application of the exciting current Ta to the exciting coil 15 is interrupted after the above operation, the valve body 25 is moved upward by the magnetic repulsion of the first and second permanent magnets 27 and 29, and the injection hole 5a is opened by the valve body 25. Closed.

In this way, this embodiment uses the first and second permanent magnets 27 without using an elastic member unlike the conventional fuel injection device.
- The injection hole 5a can be opened and closed by the valve body 25 urged by the magnetic repulsion force 29, thereby cutting off fuel injection to the internal combustion engine.

Furthermore, when the excitation coil 15 is excited, the armature 23 is magnetically attracted against the magnetic repulsion by the first and second permanent magnets 27 and 29, thereby releasing the valve body 25 from closing the injection hole 5a. It is possible to inject fuel into the internal combustion engine using As a result, the injection hole 5a by the valve body 25
It is possible to improve the opening/closing response of the internal combustion engine and supply optimized fuel to the internal combustion engine according to its required air-fuel ratio.

In the above description, the first permanent magnet 27 is arranged on the upper end surface of the core 7 and the second permanent magnet 29 is arranged on the inner surface of the valve body 25 so that the same magnetic poles face each other. 29
The injection hole 5 is activated by the valve body 25 which is biased by the magnetic repulsion force between the injection hole 5 and the valve body 25.
A was assumed to be closed, but as shown in Figure 4, one piece 2
A permanent magnet 41 is provided in the middle part of the core 7 so that the same 1ift poles are opposite to the second permanent magnet 29 provided on the inner surface of the core 7, and the upper part of the core 7 and the second permanent magnet 29
A compression spring 43 with a relatively weak elastic force is provided between the second
A fuel injection device 45 having an internal magnetic structure that closes the injection hole 5a by the magnetic repulsion between the permanent magnets 29 and 41 and the elastic force of the compression spring 43, or the inner surface of the valve body 25 as shown in FIG. A ring-shaped permanent magnet 51 is provided in the middle part of the yoke 9 so that the same magnets face the second permanent magnet 29 attached to the second permanent magnet 29 . An outer magnet-shaped fuel injection device 53 may be used in which the valve body 25 is moved to open and close the injection hole 5a.

[Effects of the Invention] Therefore, the present invention provides a fuel injection device that is capable of stably supplying fuel optimized in accordance with the actual air-fuel ratio of an internal combustion engine over a long period of time by increasing the opening/closing response of the injection hole. It is possible to provide

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a fuel injection device according to the present invention, and FIG.
The figure is a central vertical sectional view of the assembled fuel injection device, FIG. 3 is an explanatory view showing the operation, and FIGS. 4 and 5 are explanatory views showing modified examples. In the figure, 1 is a fuel injection OA device, 3 is a housing, 5 is a valve seat,
5a is an injection hole, 15 is an exciting coil, 25 is a valve body, 27 is a first permanent magnet, and 29 is a second permanent magnet.

Claims (1)

[Claims] (1), provided at one end of a hollow housing,
a valve seat with an injection hole formed in its center; a valve body that opens and closes the injection hole; first and second permanent magnets that bias the valve body with magnetic repulsion to close the injection hole; A fuel injection device comprising: an excitation coil that magnetically attracts the valve body against magnetic repulsion by the first and second permanent magnets and opens the injection hole.